Comparison of methods for tuberculosis bacteriology.

To improve efficiency of isolation of tubercle bacilli from clinical specimens, the following recommendations are presented. (i) Employ multiple specimens consisting of a combination of morning sputums for the early detection of positives, along with 24-hr sputum pools for the greatest total yield of positives. (ii) When timing is rigorously controlled, Zephiran-trisodium phosphate and sodium hydroxide-acetylcysteine are comparable, but if timing cannot rigidly be controlled, employ the Zephiran-trisodium phosphate digestion procedure to allow the greatest freedom in exposure time with the lowest kill rate to tubercle bacilli. (iii) Employ both an agar medium incubated in 5% CO(2), for the early detection of positives as well as positives in the presence of contaminants, and an egg medium, preferably with CO(2), to increase the yield of positives.